Various types of alkaline batteries (rechargeable batteries) are used as power supplies for portable electronic devices and as power supplies for electric vehicles and hybrid vehicles. One type of such an alkaline battery is a nickel-metal hydride battery, which has high energy density and superior reliability. Japanese Patent No. 4736372 describes one example of a nickel-metal hydride battery.
The nickel-metal hydride battery of Japanese Patent No. 4736372 increases the utilization ratio of the positive electrode by covering the surface of nickel hydroxide particles, which form the positive electrode active material, with a cobalt compound layer, the main component of which is cobalt oxyhydroxide.